Title of Research:
Reduction of Escherichia coli O157:H7 and Salmonella spp. Using Dry Chilling in Small Processing Plant Environments
Texas Tech University, Lubbock, TX
Drs. A.W. Tittor, M.G. Tittor, M.B. Brashears, J.C. Brooks,
and M.F. Miller
- Determine and quantify the reduction of growth of E. coli O157:H7 and
Salmonella spp. on beef tissue following two chilling methods (water spray chilling and dry chilling)
used by small processing plants.
- Determine the use of dry chilling as a Critical Control Point (CCP).
Small processors are continually striving to explore cost
effective means to reduce pathogenic bacteria on beef carcasses.
Currently, small beef or custom beef processors allow beef carcasses
to dry age for 28 days to improve beef palatability. The results
from this study have shown that dry chilling for 21 days is an
effective intervention in reducing E. coli O157:H7 and
Salmonella spp. on fresh beef carcasses compared to
conventional water spray chilling/wet ageing. This recommendation is
compared to Buege and Ingram (2003) which suggests a 6-day aging of
carcasses and critical limits of cooler temperature, as well as days
of aging. Although a decrease in recovery was seen across both
pathogens as well as both treatments, the recommendation from the
above results show that at 21 days of aging beef tissues can achieve
an approximate 4-log reduction of pathogenic bacteria by dry
This study reinforces the advantage of dry chilling/ageing of beef
carcasses in reducing the levels of E. coli O157:H7 and
Salmonella spp. when compared to the conventional water spray
chilling/wet ageing. Plants will, however, need to validate that
their methodology achieves these parameters. This research should
decrease their operating costs while helping them to ensure food
safety and public health protection.
The full report on this research can be found on the Fiscal Year 2005 table under the column Food Safety Technologies - Additional Information.